1. Field of Invention
The invention relates to apparatus for enabling person(s) trapped in a stopped elevator car to evacuate safely, and more particularly to such an elevator evacuation apparatus with improved characteristics.
2. Description of Related Art
Components of a first conventional elevator evacuation arrangement mounted in a machine room (not shown) are shown in FIG. 1 and comprise a motor 1, a drive sheave 2 driven by the motor 1, a plurality of parallel ropes 3 run through rope grooves of the drive sheave 2, the ropes 3 having one ends connected to a top of an elevator car (not shown) and the other ends connected to a counterweight (not shown), and a brake 4 mechanically connected to the motor 1. The brake 4 is adapted to actuate to stop the rotation of the drive sheave 2 in case of emergency (e.g., power outage).
Components of the first conventional elevator evacuation arrangement further comprise a lever 5 having a shaft 5a, and a cam 6. Typically, a skilled mechanic is called to enter the machine room to manually push the lever 5 to actuate the cam 6 via the shaft 5a. The cam 6 in turn presses down a member (e.g., plunger) to release the brake 4. Thereafter, the drive sheave 2 is able to rotate again for lowering the car to a next floor since it is typical that the car did not stop at the correct floor location when the emergency occurred. Eventually, person(s) trapped in the car can evacuate safely.
The first conventional elevator evacuation arrangement has the following disadvantages. For example, it requires calling a skilled mechanic to come to the site for troubleshooting. This inevitably will delay the precious saving time and it is highly undesirable. Moreover, a successful evacuation depends on the unbalanced state (i.e., weight of the counterweight being not equal to that of the stopped car so that the car is capable of lowering in response to releasing the brake 4). Hence, the skilled mechanic is useless if the car is in a balanced state.
A second conventional elevator evacuation arrangement is shown in FIG. 2 in which a rod 7a is extended out of a member (e.g., plunger) of a brake 7 and a spring 7b is put on shank of the rod 7a. A skilled mechanic has to press the spring depressible rod 7a to release the brake 7 via the plunger in the troubleshooting procedure. The second conventional elevator evacuation arrangement also has the disadvantage of requiring a skilled mechanic to come to the site for troubleshooting.
A third conventional elevator evacuation arrangement is shown in FIG. 3 in which a disc brake is provided between a drive sheave 2 and a motor 1, and the brake comprises brake pads 8a and a disc 8. In operation, a skilled mechanic may manually push a lever 8b to actuate the brake pads 8a. The brake pads 8a in turn urge against the disc 8 to release the brake. The third conventional elevator evacuation arrangement still has the disadvantage of requiring a skilled mechanic to come to the site for troubleshooting.
There have been numerous suggestions in prior patents for enabling person(s) trapped in a stopped elevator car to evacuate safely. For example, U.S. Pat. No. 6,739,431 discloses an elevator escape device. Thus, continuing improvements in the exploitation of elevator evacuation apparatus are constantly being sought.